The present invention relates to multi-barrel guns in fighter aircraft, and, in particular, to controlling the flow of gases from the gun barrels.
The use of high rate of fire guns in aircraft, in particular, multi-barrel gatling type guns which can fire up to 6,000 rounds per minute as used in F-15, create special problems. Gun muzzle gases are the source of many gun/aircraft interface problems. Typical aircraft problems associated with gunfire generated gases include: gun gas induced engine failure, excessive gun/aircraft interface loads, aircraft surface damage, impaired pilot visibility, unacceptable visual and thermal signatures due to secondary flash, and excess gun bay gases causing fire and explosions.
The types of hardware that have been developed in the past for the express purpose of gun gas management are quite diverse, but can be broadly categorized as either muzzle devices, which are attached directly to the gun muzzle, or blast deflectors, which generally attach to structure surrounding the gun muzzle. Muzzle devices are typically employed for one or more of the following reasons: suppression of secondary flash, recoil force reduction, redirection and/or diffusion of the axially flowing muzzle gases, and torque generation to assist rotation of a gatling gun. Some of these characteristics tend to be negatively impacted by other, for example, a flash supressing device cannot usually be designed to also generate torque (the resultant turbulence causes improved air mixing with the hot gases, thereby promoting secondary flash). Blast deflectors are typically rugged metal fabrications that protect more fragile aircraft structure from the muzzle gas heat and pressure, muzzle debris and percussion waves from the passing projectile. They usually partially surround the gun muzzle such that the muzzle gases expand in the direction of the open side. Blast deflectors sometimes provide lateral and vertical support to the gun muzzle, and may contain a gas seal that inhibits rearward flow into the gun compartment. Typical gun installations usually employ some sort of muzzle device or blast deflector, and in some cases, both are used. Examples of the latter are the 20-mm F-4E internal gun system, the 20-mm GPU-2/A gun pod and the 30-mm GPU-5/A gun pod. The GPU-5/A contains a diverter attached to the gun muzzle and a collector that surrounds the diverter and gun muzzle (the collector forms the entire nose of the pod). However, the GPU-5/A diverter is a simple baffle plate design that does not generate torque and is not an efficient recoil reducer. The GPU-5/A also does not employ the duct component, instead gases exhaust directly to the atmosphere through perforations in the lower quadrant of the collector.
Improvements in this area are illustrated by U.S. Pat. Nos. 4,574,682 and 3,703,122. These patents are directed at devices attached to the multi-barrel gun muzzle and assist in providing torque to turn the barrels and reduce the amount of recoil. Although these devices perform as stated, additional control of the gas is needed as it leaves the aircraft as well as further control of the gas as it leaves the gun muzzle.
Thus, there exists a need for a means of preventing many of the problems associated with gatling gun's muzzle gas.